After this I paint the areas where I want hazard stripes in black and add a matte wash. The reason for this comes later.
The tracks is painted with a mix of black, burnt umber and orange oil paint. This is mixed with a lot of mineral spirits. The consistency is almost as a wash but a little heavier. I dabb paper tissue to remove the exes paint.
Once dried I draw in the highlights with a graphite pencil.
After this I paint the hazard stripes and add decals.
The reason for painting yellow hazard stripes on top a black surface is this. In order to get good coverage I have to do several coats of paint. This is good because I will use a hobby knife to introduce scratches and battle damage. This means that I have a top layer to remove, reveling the black underlaying black. It looks more realistic and is much faster.
Oh I have not put a single layer of varnish on the model, even if I have started to work with oils and mineral spirits.
First off, the silver spray coat already contains more varnish than other acrylics so you already have a protective layer.
Second, just applying mineral spirits and oils will not remove any paint. It is rubbing and punching it around. So apply it, quickly do adjustments and then let it be until it fully dries.